Various imidazole derivatives, which can inhibit the action of angiotensin II, have been used for the treatment of hypertension caused by angiotensin II. Angiotensin II is produced by an angiotensin converting enzyme from angiotensin I, which is formed from angiotensinogen by the action of renin. Angiotensin II, which is a potent vasoconstrictor interacting with specific receptors on cell membrane, has been reported to cause hypertension in mammals including human beings.
Many studies have been made to search for an antagonist which inhibits the action of angiotensin II on the receptors of its target cell in order to suppress the elevation of blood pressure. As a result, many imidazole derivatives have been developed (see A. T. Chiu et al., Eur. J. Pharm., 157, 13(1981); P. C. Wong et al., J. Pharmacol. Exp. Ther., 247, 1(1988); and P. C. Wong et al., Hypertension, 13, 489(1989)).
As a representative of these compounds, for example, D. J. Carini et al. reported in J. Med. Chem., 34, 2525(1990) imidazole derivatives of the following formula (A): ##STR2##
Despite these discoveries, however, needs have continued to exist for the development of more effective agents which possess enhanced antagonistic property against angiotensin II.